Expand Django and DRF permission detection

[bjcorder]

Summary

• Read static DRF settings permission and authentication defaults and apply them only when view-level declarations are absent.
• Preserve per-action permission and authentication overrides in route metadata, overriding class-level declarations for that action.
• Recognize class-level method_decorator guards and retain local recursive mixin-chain evidence.
• Normalize parenthesized multiline Python imports for Django handler resolution.
• Add django_dynamic_settings_default as an advisory diagnostic for dynamic settings defaults.

Verification

• cargo check --workspace --all-targets --locked
• cargo test --workspace --all-targets --locked

Closes #107